A typical fuel cell includes a plurality of bipolar plates with membrane electrode assembly (MEA) membranes interposed therebetween. Flow pathways are formed on the sides of the bipolar plates to bring reactants (in a simplest case, hydrogen and oxygen) adjacent the MEA, with the result that the overall cell converts the reactants into a product (typically water) and simultaneously generates an electric current through the stack.
Typical bipolar plates are formed of graphite with the graphite initially being provided in sheets and then machined to include the recesses through which the reactants flow. To optimize performance, the location, shape and size of these recesses and the bipolar plates themselves must be carefully controlled. Due to the unique nature of graphite material, it has not heretofore been successfully molded into bipolar plates. Rather, the graphite sheets have required machining to form the recesses. The graphite material is not particularly easily machined. Hence, the bipolar plates typically end up comprising at least thirty percent (and often a majority) of the overall cost of the fuel cell. Accordingly, a need exists for a bipolar plate which can be formed in a different and less expensive fashion while still maintaining the performance requirements required for the bipolar plate.
Additionally, typical prior art bipolar plates formed of graphite are exceptionally rigid. Thus, the entire fuel cell is somewhat susceptible to performance interruption should the bipolar plates become cracked. In many environments where fuel cells are to be utilized, shock loads exist that make the prior art bipolar plates susceptible to such cracking or other failure. Accordingly, a need exists for bipolar plates which can maintain fuel cell function but which are sufficiently flexible and have sufficient strength to resist cracking or other failure when shock loads are experienced.